AutoCAD 2013 Materials Disaster!

[Alqassab]

I'm currently working on a 3D school project and I've been having material problems from the very start.

Some of the materials would keep changing by themselves after I close and reopen the file, Even though I save frequently and before quitting. 

Even when I change the materials back they keep changing or reverting back to "Global" material by themselves! 

This is Driving me INSANE!!!!!!!!!!!!! 

Lastly I'm adding some signage to the project as blocks, I've created the 3D signs in seperate DWG files and inserting them as a Block to the main model. I save, quit and reopen, and now all the materials are messed up!

What is the MATTER WITH AUTOCAD?????????????????????

See attached image of the materials on the signs all messed up and the material of the sign in its file.

I DON'T UNDERSTAND!!!!!!!!!!!!! 

V------ MATERIALS ALL SCREWED UP ------V

V-------- NORMAL MATERIALS IN SIGN FILE --------- V

HEEEEEEEEEEEEEEEEEEEEEEELLLLLLLLLLLLLLLLLLLLLLLLLLLLLLPPPPPPPPPPPPPPPPPPPPPPPPPPPPPP

[ntellery]

Yes the materials implimentation is pretty dodgy and has been for several releases.

Most of my materials are applied via aecObjects and not via the direct attach method but my materials drop off often.  Odin of Archidigm.com recons it's if you started in an earlier release.  He thinks (as I understand him) if you start with a 13 template in 13 it won't happen.  Not verified this myself.

I have found that reselecting the display rep just before you render usually reattaches the materials but some can fall off altogether.

Interesting observation here.  If you find materials not rendering and do a purge, it will actually purge these materials that have dropped off.  If you go thru the process to get them to reattach, ie, select display rep again, they will not purge.  Something bad happening here.

If they still won't attach, I found yesterday, that going into the materials pallete and opening the materials that don't show their swatch properly, double clicking on the material or opening up the editor, seems to reset and reattach the material.  

I have assumed that it's the implementation for ACA as I haven't seen anyone else report these issues but it may extend to autocad as well.

Not a disaster but not what you expect from such an expensive package.